1. Field of the Invention
The present invention relates to a linear compressor, more particularly, in which a sealing protrusion is formed in a cylinder for line contact with the cylinder and an exhale cover. With this configuration, the linear compressor provides a capability of improving its performance and reliability, by effectively sealing the cylinder and the exhale cover, and by preventing a transformation of the cylinder.
2. Description of the Related Art
Generally, a linear compressor is a machine to inhale, to compress, and to discharge fluid by linearly reciprocating a piston within a cylinder, by means of linear driving force of a linear motor.
FIG. 1 shows the linear compressor, in accordance with the prior art, and FIG. 2 shows a structure of an exhale part of the linear compressor, in accordance with the prior art.
In a hermetic casing 2 of the conventional linear compressor, a frame 4 connected to the cylinder 3 and a back cover 6 positioned in a rear of the frame 4 and provided with an inlet 5 are equipped. The frame 4 and the back cover 6 are upheld in the hermetic casing 2 by a main damper 7 and a subsidiary damper 8, so as to absorb a shock (see FIG. 1).
The linear motor 10 is mounted between the frame 4 and the back cover 6, which generates driving force to compress fluid.
The linear motor 10 is divided by a stationary part and a movable part. The stationary part includes an outer core 11, an inner core 12, and a coil 13 with a magnetic field. The movable part includes a magnet 14 that linearly reciprocates by magnetic force around the coil 13, and a magnet frame 15 which the magnet 14 is fastened to.
The piston 16 is set in the cylinder 3, which receives linear driving force from the magnet 14, linearly reciprocates, and compresses fluid within the cylinder 3.
In a rear of the piston 16, a flange 17 is formed to be fixed to the magnet frame 15. A main spring 18 is disposed between the flange 17 and the frame 4, and a subsidiary spring 19 is disposed between the flange 17 and the back cover 6, so that the piston 16 is elastically suspended.
The piston 16 is in a shape of a cylinder, which is open at its rear. An inhale passage 20 where fluid is entered is provided therein, and a plurality of inhale ports 21 is provided in its front.
In a front of the piston 16, there is an inhale valve 22 for opening and closing the inhale port 21. Fastened to the piston 16 by a connection member, the inhale valve 22 gets elastically bended, depending on a pressure difference between the inside and the outside of the inhale port 21, thus opening and closing the inhale port 21.
The cylinder 3 is in a shape of a cylinder, which is open at both sides, the piston 16 is inserted in one end, and the exhale part 30 for discharging compressed fluid is placed in the other end. The piston 16 and the exhale part 30 make a compression chamber C.
The exhale part 30 includes an inner exhale cover 32 located in a front of the compression chamber C of the cylinder 3 and provided with an exhale hole 31, an outer exhale cover 33 positioned at a regular interval from an outer surface of the inner exhale cover 32, and an exhale valve 34 elastically suspended in the inner exhale cover 32 to open and close the compression chamber C of the cylinder 3 (see FIG. 2).
The exhale valve 34 is suspended in the inner exhale cover 32 by an exhale spring 35. The exhale spring 35 is a coil spring to give the elasticity toward a direction that the exhale valve 34 closes the compression chamber C.
The inner exhale cover 32 is in a shape of a cap, so as to make an exhale space where fluid is discharged in the front of the compression chamber C of the cylinder 3. The outer exhale cover 33 is in a shape of the cap, so as to make a predetermined space, apart from the outer surface of the inner exhale cover 32 by predetermined distance.
In a circumference of the inner exhale cover 32, a main flange 36 is radially protruded, while in a circumference of the outer exhale cover 33, a subsidiary flange 37 is radially protruded to confront the main flange 36.
The main flange 36 and the subsidiary flange 37 respectively have a connection hole, fastened to the frame 4 by a bolt 38.
A connection groove 39 for connecting the bolt 38 is formed in a side of facing the main flange 36 in the frame 4.
A sealing part 40 is radially protruded in a circumference of the cylinder 3, confronting the main flange 36, so that fluid does not leak through a slit between the cylinder 3 and the inner exhale cover 32.
The linear compressor having the conventional structure of the exhale part operates in the following sequence.
In operation of the linear motor 10, the magnet 14 linearly reciprocates, its linear driving force is delivered to the piston 16 through the magnet frame 15. The piston 16 moves back and forth within the cylinder 3.
Fluid entered in the hermetic casing 2 is inhaled into the compression chamber C of the cylinder through the inhale passage 20 in the piston 16, is compressed by the piston 16, allows the exhale valve 34 to be opened, and is discharged to the outside through the inner exhale cover 32 and the outer exhale cover 33.
The inner exhale cover 32 and the outer exhale cover 33 are fastened to the frame 4 by the bolt 38. When the bolt 38 is tightened, the inner exhale cover 32 gives pressure to the sealing part 40 of the cylinder 3, and then the main flange 36 is closely adhered to the sealing part 40.
As a result, when the main flange 36 of the inner exhale cover 32 is closely adhered to the sealing part 40 of the cylinder 3, fluid is prevented against leaking between the inner exhale cover 32 and the cylinder 3.
However, in the linear compressor with the conventional exhale part, when the inner exhale cover 32 and the outer exhale cover 33 are connected to the frame 4, power is excessively delivered to the cylinder 3 through the inner exhale cover 32. It brings problems that the cylinder 3 may be transformed, and a gap between the piston 16 and the cylinder 3 may be transformed, thus reducing a performance and reliability of the linear compressor.
If power transmitted from the inner exhale cover 42 to the cylinder 3 gets reduced, in order to protect a transformation of the cylinder 3, the main flange 36 is not closely adhered to the sealing part 40. Therefore, fluid may leak between the inner exhale cover 32 and the cylinder 3.